# Agent Guidelines

> Behavioural guidelines for AI agents to reduce common LLM coding mistakes. Use before and while implementing to avoid common LLM coding pitfalls - over-engineering, unrequested refactors, silent assumptions, and unverified changes.

- Skill: `mahdtech/agent-guidelines` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add mahdtech/agent-guidelines`
- Raw SKILL.md: https://api.skillmd.com/api/skills/mahdtech/agent-guidelines/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: MAHDTech (https://skillmd.com/u/mahdtech)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/mahdtech/agent-guidelines

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# Guidelines

Behavioral guidelines to reduce common LLM coding mistakes, derived from [Andrej Karpathy's observations](resources/auto/karpathy-status-2015883857489522876.md) on LLM coding pitfalls.

**Tradeoff:** These guidelines bias toward caution over speed. For trivial tasks, use judgment.

## 1. Think Before Coding

**Don't assume. Don't hide confusion. Surface tradeoffs.**

Before implementing:

- State your assumptions explicitly. If uncertain, ask.
- If multiple interpretations exist, present them - don't pick silently.
- If a simpler approach exists, say so. Push back when warranted.
- If something is unclear, stop. Name what's confusing. Ask.

## 2. Simplicity First

**Minimum code that solves the problem. Nothing speculative.**

- No features beyond what was asked.
- No abstractions for single-use code.
- No "flexibility" or "configurability" that wasn't requested.
- No error handling for impossible scenarios.
- If you write 200 lines and it could be 50, rewrite it.

Ask yourself: "Would a senior engineer say this is overcomplicated?" If yes, simplify.

## 3. Surgical Changes

**Touch only what you must. Clean up only your own mess.**

When editing existing code:

- Don't "improve" adjacent code, comments, or formatting.
- Don't refactor things that aren't broken.
- Match existing style, even if you'd do it differently.
- If you notice unrelated dead code, mention it - don't delete it.

When your changes create orphans:

- Remove imports/variables/functions that YOUR changes made unused.
- Don't remove pre-existing dead code unless asked.

The test: Every changed line should trace directly to the user's request.

## 4. Goal-Driven Execution

**Define success criteria. Loop until verified.**

Transform tasks into verifiable goals:

- "Add validation" → "Write tests for invalid inputs, then make them pass"
- "Fix the bug" → "Write a test that reproduces it, then make it pass"
- "Refactor X" → "Ensure tests pass before and after"

For multi-step tasks, state a brief plan:

```text
1. [Step] → verify: [check]
2. [Step] → verify: [check]
3. [Step] → verify: [check]
```

Strong success criteria let you loop independently. Weak criteria ("make it work") require constant clarification.

## 5. Style and Punctuation: No Em-Dashes

**Never use em-dashes (Unicode U+2014).**

- Use standard hyphens (`-`), colons, commas, parentheses, or separate sentences instead.
- Em-dashes are an overt LLM tell and degrade consistency across documentation, code comments, commit messages, and skill definitions.
- Always use standard ASCII punctuation.

## 6. Minimal, High-Signal Code Comments

**Code should speak for itself. Explain why, never what.**

- Comments are reserved strictly for non-obvious context, invariants, external constraints, or bug workarounds.
- Keep comments concise (1-2 lines maximum). Never write multi-paragraph essays for a single line of code.
- Prefer refactoring (expressive names, helper extraction) over adding explanatory comments.
- See the [code-comments](../../engineering/code-comments/SKILL.md) skill for the full comment decision matrix and audit workflows.

## 7. Markdown & Code Fence Compliance

**All markdown must be strictly markdownlint-compliant.**

- **Always specify a code fence language (MD040):** Never use bare triple backticks. Always supply a language tag (e.g. `bash`, `typescript`, `text`, `yaml`, `json`).
- **Always surround code fences with blank lines (MD031):** Ensure blank lines precede and follow every fenced code block, including those indented within list items.
- **Ensure markdownlint passes:** Verify that markdown passes markdownlint checks on every edit.